Multi-shell transition metal oxide hollow spheres show great potential for applications in energy storage because of their unique multilayered hollow structure with large specific surface area, short electron and charge transport paths, and structural stability. In this paper, the controlled synthesis of NiCo2O4, MnCo2O4, NiMn2O4multi-shell layer structures was achieved by using the solvothermal method. As the anode materials for Li-ion batteries, the three multi-shell structures maintained good stability after 650 long cycles in the cyclic charge/discharge test. Thein situtransmisssion electron microscope characterization combined with cyclic voltammetry tests demonstrated that the three anode materials NiCo2O4, MnCo2O4and NiMn2O4have similar charge/discharge transition mechanisms, and the multi-shell structure can effectively buffer the volume expansion and structural collapse during lithium embedding/delithiation to ensure the stability of the electrode structure and cycling performance. The research results can provide effective guidance for the synathesis and charging/discharging mechanism of multi-shell metal oxide lithium-ion battery anode materials.
Keywords: anode materials; in situ transmission electron microscopy; lithium-ion battery; multi-shell structure.
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